Device for locking electric incandescent lamps in their lamp holders



H. FRANcls Jan. 8, 1924.

DEVICE FOR LOCKING ELECTRIC INCANDIISCENT LAMPS IN THEIR LAMPHOLDERS Filed Nov.

Patented Jan. 8, 1924.

UNITED STATES HENRY FRANCIS, OF SHEPHERDS BUSH, ENG-LAND.

DEVICE FOR LOCKING ELECTRIC INCANDESCENT LAMPS THEIR LAMP HOLDERS.

Application filed November 15, 1921. Serial No. 515,260.

To all whom it may concern.

Be it known that I, HENRY FRANoIs, a subject of the King of Great Britain and Ireland, and a resident of Shepherds Bush, county of London, England, have invented a certain new and useful Improvement in a Device for Locking Electric Incandescent Lamp-s in Their Lamp Holders, of which the following is a specification.

This invention relates to a device for locking electric incandescent lamps in their lampholders in order to render impossible .the removal of said lamps from said holders until the glass bulb has been destroyed an the lamp is of no further use.

Broadly, the device consists of a metal collar constituted by two parts, one of which movably fits inside the other, so that the length of said two-part collar can be varied, means being provided to lock said parts together when in adjusted position on the lampholder, that is to say, with the upper end of the one part of the collar butting against the enlarged screw portion of the lampholder, whilst the lower end of the other part of said collar is in close abutment with the upper end of the glass bulb when in the holder.

In this position the lamp cannot be lifted in the lampholder sufficiently to turn it and disengage the pins of the lamp from the bayonet slots in the lampholder until the glass bulb is destroyed.

In order that the invention may be the more readily understood, reference is to be 'had-to the following description and accom panying sheet of drawings, which illustrate practical ways of carrying out the invention, and wherein Figure 1 is a view of an externally screwthreaded inner part of a collar.

Figure 2 is a top plan view thereof.

Figure 3 is a vertical sectional view of an internally screw-threaded outer part of the collar.

Figure 4 is a plan view, partly in section, illustrative of the manner in which the two parts are locked together.

Fi e 5 is a view, partly in section, illustrative of the applicatlon of the invention.

Figures 6 and 7 are views illustrative of two modified forms-of a. collar.

Figure 8 is a vertical sectional view of the outer part of a collar used with either of the iner parts shown in Figures 6 and 7.

Like letters of reference indicate corresponding parts in the several figures.

In carrying out the invention, and referring first to igures- 1 to 5, the collar consists of an inner and externally screwthreaded member o-Figures 1 and 2-and an internally screw-threaded outer member Z Figure 3screwing one upon the other as in Figures 4 and 5, said inner member (1 having its outer peripheral surface serrated wiith a number of vertically disposed notches a thereon, whilst the outer member I) is provided internally with a spring catch 1) aflixed to said member I; in any suitablemanner, or formed integral therewith, the arrangement being such that, as the members an and b are screwed together, the spring catch 6 rides over the screw threads of the member a, but looks in-one or the other of the notches a of said member a when reverse rotation is attempted, thus allowing saidmember a to be rotated only in one direction, which is downwardly, i. e. lengthening the collar as a whole.

In use, the collar is placed upon the lampholder, with theupper end a of the inner member a butting against the enlarged screw-threaded portion 0 of said holder, as in Figure 5. The lamp is then inserted in the lampholder in the usual way, and the collar'then adjusted lengthwise, by screwing down the member 1) till the lower end of said member 12 is in close abutment with the upper end d of the glass bulb b, said member I) being locked to the member a by its spring catch 1) engaging in a notch 01, of the member e.

In this position the lamp cannot be lifted in its holder sufliciently to revolve it and disengage the pins of said lamp from the bayonet slots of the holder until the glass bulb d is destroyed.

As an alternative method of adjusting the two members 01 and b constituting a. collar, use is made of a series of concentric serrationsa around the peripheral surface of the inner member a as shown in Figure 6, or, as shown in Figure 7, use may be made of lines of vertical serrations a parallel with the axis of the collar, or inclined lines of serrations may be employed,

The outer member I) for use with these forms of serrated inner members will be formed with a plain interior and the springs 1) arranged vertically therein as shown in Figure 8.

To adjust and lock the members a and b, shown in Figures 6, 7 and 8, lengthwise, the outer member 6 is pulled towards the glass bulb until it abuts against the upper end of said glass bulb, the spring catch 6 of said member 6 engaging in the serration of the member at opposite it when in that position.

As a convenient method of destroying the glass bulb, when required, a rubber, leather, canvas, or other bag may be placed over the bulb and held in position while the bulb is broken by a blow upon the outside -of the bag, thus the glass is retained in the bag, and the danger from flying particles of glass obviated.

I claim p 1. A device for locking an electric incan v descent lamp in its holder, characterized by a threaded and notched holder, and an adj ustable collar carrying a catch for engaging with said. notch whereby the collar can be lengthened but cannot be shortened, the ends of said collar engaging respectively with the enlarged threaded portion of the holder and the upper end of the glass bulb.

2. A device for locking an electric-incandescent lamp to its holder, characterized by a collar consisting of an inner and externally screw-threaded member, a series of vertically disposed notches across the threads of said member, an outer and internally screwthreaded outer member screwing, on said inner member, and a spring catch carried by said outer member and interior thereof to engage in the notches of said inner mem- In testimony whereof I have afii'xed my signature hereto this 24th day of Ooctober 1921.

HENRY FRANCIS. 

